Blumstein et al. look to evolutionary theory regarding signaling in animal species to try to draw out some general rules of thumb that they think might be useful for diplomats and politicians in matters of foreign policy. The rationale for the exercise is that “By capitalizing on solutions derived by evolution over 3.5 billion year of life of Earth, we may identify ideas that otherwise might not have been explored in a policy context potentially offering quick, novel and effective options to increase strategic and combat effectiveness.”
None of the eight rules of thumb, however, are novel propositions or observations, and some – like the eighth, “it’s essential to know your audience” – are mainstays of international relations literatures and diplomatic folklore or commonsense. (Not to say such wisdom is always acted on!) The core idea in several of them is that signals will not reliably convey their message unless they are actions (or words) that would be more costly for a potential bluffer to take. This idea has been familiar in Economics and Political Science research for some time now, and in this specific formulation it derives not from evolutionary theory but from developments in information economics in the late 1960s and early 1970s.
There are indeed some significant parallels between the strategic problems facing animals competing over territory or mates and that between two states, or a state and non-state group, at odds over territory or public policy. In both cases violent conflict is typically costly and thus something both sides would like to avoid. But both sides would also prefer that the other side concede more of whatever resources or goods (which might be symbolic, in the human case) are at stake. In both contexts, then, all can ideally be made better off if they can develop some kind of signaling system that allows the more motivated or strong types to credibly reveal this, so avoiding violent contests when a stronger or more motivated party faces a weaker or less motivated antagonist. It is fascinating – though perhaps not so surprising, once we have seen the analogy and realized that evolution can sometimes select “best reply” strategies even without cognition – that animal contests (including sexual selection) often exhibit complex strategies of costly signaling.
What is less clear is whether there are specific findings from the study of signaling in (non-human) animal systems that have interesting or novel implications for diplomats and politicians engaged in international affairs. As noted, none of these eight general rules of thumb are results or arguments that did not already emerge from social science studies of signaling in human contexts. Perhaps, however, as the study of signaling in animal contexts proceeds it will produce findings that suggest novel ideas about signaling in human contexts.
For example, the canonical story about the peacock’s tail has, according to more recent research, gotten somewhat murkier. There has always been the following theoretical objection: If a bigger tail with more eyespots signals greater quality, then greater fitness should select out variation in tails so that residual variation in tail quality is not correlated with fitness. Thus, in evolutionary equilibrium, expected fitness must be equal across larger and small tails, with the handicap of a larger train exactly compensating for a bird’s greater underlying quality.
Empirically, the original study found a correlation between number of eyespots and mating success in a population in Britain. However, more recent studies based on populations in France and Japan reached different conclusions. In the French group, number of eyespots was unrelated to mating success, but the length of the train was. In the Japanese birds, there was no correlation for either one. In studies of three different North American populations there was also no correlation between number of eyespots and mating success (at least until almost the bird’s eyespots were clipped off).
It could be that some other feature of the tail is a signal of mate quality. According to Erol Akcay, an evolutionary biologist who is my source for this information, we just don’t know, and we also don’t have studies that directly test whether the peacock’s tail is a costly signal, since cost has not been measured and related to “quality.” Akcay (personal communication) thinks it is likely that peacock’s tail is a signal of some kind, since it is hard to see it evolving without having some adaptive value. But he thinks “what exactly it is a signal of and whether it is honest because it’s costly are open questions at this point.”
So perhaps things are not so straightforward. This is surely also the case for diplomacy. For example, it is not uniformly true that “honest signals will be costly” (Lesson 1) or that (Lesson 4) “threats should be costly.” At a minimum, these claims depend on a prior assumption that we are talking about a situation in which the signaler can have a strong incentive to misrepresent its preferences or type – to bluff – to the target. In some diplomatic contexts, “cheap talk” can be informative because the parties’ interests are sufficiently aligned that misrepresentation can be counterproductive. Or, it can be the case that in signaling between governments there are so many sources of publicly available information about what is going on that misrepresentation is not a big concern. Finally, when states are signaling over multiple dimensions of policy, which is often the case, cheap talk can be informative even when there are incentives to misrepresent.#
A final comment is that to the extent that we do put stock in these costly signaling claims as rules of thumb, they may actually argue against the notion that evolutionary (or economic) theory can increase diplomats’ tactical success in contests. The point of these arguments is that contests are like auctions in which the side that is genuinely more resolved or more capable is more likely to win. The advice “Make your signals of resolve (or reassurance, if seeking peace) costly!” only makes sense if you actually are that resolved or you are that willing to risk a disadvantage in order to get to peace. There is a parallel here with “Lesson 3: Unexpected signals may be more effective,” where the authors suggest that “individual citizens lining up to help others (as often occurs after natural disasters) are truly meaningful gestures.” The advice “deliberately make your gestures of reconciliation spontaneous in order to make them effective!” is a bit of contradiction in terms.
Evolutionary theory regarding signaling in animal contests may yet produce novel and interesting insights into signaling in roughly parallel human contexts. Given the incredible complexity and diversity of animal signaling systems, I would expect that this could be the case. But I’m not sure if these very high level rules of thumb optimally exploit the potential in this area.
James D. Fearon
Department of Political Science
Stanford University
